/*
 * contrib/btree_gist/btree_date.c
 */
#include "postgres.h"

#include "btree_gist.h"
#include "btree_utils_num.h"
#include "utils/builtins.h"
#include "utils/date.h"

typedef struct
{
    DateADT        lower;
    DateADT        upper;
} dateKEY;

/*
** date ops
*/
PG_FUNCTION_INFO_V1(gbt_date_compress);
PG_FUNCTION_INFO_V1(gbt_date_fetch);
PG_FUNCTION_INFO_V1(gbt_date_union);
PG_FUNCTION_INFO_V1(gbt_date_picksplit);
PG_FUNCTION_INFO_V1(gbt_date_consistent);
PG_FUNCTION_INFO_V1(gbt_date_distance);
PG_FUNCTION_INFO_V1(gbt_date_penalty);
PG_FUNCTION_INFO_V1(gbt_date_same);

static bool
gbt_dategt(const void *a, const void *b, FmgrInfo *flinfo)
{
    return DatumGetBool(
                        DirectFunctionCall2(date_gt, DateADTGetDatum(*((const DateADT *) a)), DateADTGetDatum(*((const DateADT *) b)))
        );
}

static bool
gbt_datege(const void *a, const void *b, FmgrInfo *flinfo)
{
    return DatumGetBool(
                        DirectFunctionCall2(date_ge, DateADTGetDatum(*((const DateADT *) a)), DateADTGetDatum(*((const DateADT *) b)))
        );
}

static bool
gbt_dateeq(const void *a, const void *b, FmgrInfo *flinfo)
{
    return DatumGetBool(
                        DirectFunctionCall2(date_eq, DateADTGetDatum(*((const DateADT *) a)), DateADTGetDatum(*((const DateADT *) b)))
        );
}

static bool
gbt_datele(const void *a, const void *b, FmgrInfo *flinfo)
{
    return DatumGetBool(
                        DirectFunctionCall2(date_le, DateADTGetDatum(*((const DateADT *) a)), DateADTGetDatum(*((const DateADT *) b)))
        );
}

static bool
gbt_datelt(const void *a, const void *b, FmgrInfo *flinfo)
{
    return DatumGetBool(
                        DirectFunctionCall2(date_lt, DateADTGetDatum(*((const DateADT *) a)), DateADTGetDatum(*((const DateADT *) b)))
        );
}



static int
gbt_datekey_cmp(const void *a, const void *b, FmgrInfo *flinfo)
{
    dateKEY    *ia = (dateKEY *) (((const Nsrt *) a)->t);
    dateKEY    *ib = (dateKEY *) (((const Nsrt *) b)->t);
    int            res;

    res = DatumGetInt32(DirectFunctionCall2(date_cmp, DateADTGetDatum(ia->lower), DateADTGetDatum(ib->lower)));
    if (res == 0)
        return DatumGetInt32(DirectFunctionCall2(date_cmp, DateADTGetDatum(ia->upper), DateADTGetDatum(ib->upper)));

    return res;
}

static float8
gdb_date_dist(const void *a, const void *b, FmgrInfo *flinfo)
{
    /* we assume the difference can't overflow */
    Datum        diff = DirectFunctionCall2(date_mi,
                                           DateADTGetDatum(*((const DateADT *) a)),
                                           DateADTGetDatum(*((const DateADT *) b)));

    return (float8) Abs(DatumGetInt32(diff));
}


static const gbtree_ninfo tinfo =
{
    gbt_t_date,
    sizeof(DateADT),
    8,                            /* sizeof(gbtreekey8) */
    gbt_dategt,
    gbt_datege,
    gbt_dateeq,
    gbt_datele,
    gbt_datelt,
    gbt_datekey_cmp,
    gdb_date_dist
};


PG_FUNCTION_INFO_V1(date_dist);
Datum
date_dist(PG_FUNCTION_ARGS)
{
    /* we assume the difference can't overflow */
    Datum        diff = DirectFunctionCall2(date_mi,
                                           PG_GETARG_DATUM(0),
                                           PG_GETARG_DATUM(1));

    PG_RETURN_INT32(Abs(DatumGetInt32(diff)));
}


/**************************************************
 * date ops
 **************************************************/



Datum
gbt_date_compress(PG_FUNCTION_ARGS)
{
    GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);

    PG_RETURN_POINTER(gbt_num_compress(entry, &tinfo));
}

Datum
gbt_date_fetch(PG_FUNCTION_ARGS)
{
    GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);

    PG_RETURN_POINTER(gbt_num_fetch(entry, &tinfo));
}

Datum
gbt_date_consistent(PG_FUNCTION_ARGS)
{
    GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
    DateADT        query = PG_GETARG_DATEADT(1);
    StrategyNumber strategy = (StrategyNumber) PG_GETARG_UINT16(2);

    /* Oid        subtype = PG_GETARG_OID(3); */
    bool       *recheck = (bool *) PG_GETARG_POINTER(4);
    dateKEY    *kkk = (dateKEY *) DatumGetPointer(entry->key);
    GBT_NUMKEY_R key;

    /* All cases served by this function are exact */
    *recheck = false;

    key.lower = (GBT_NUMKEY *) &kkk->lower;
    key.upper = (GBT_NUMKEY *) &kkk->upper;

    PG_RETURN_BOOL(
                   gbt_num_consistent(&key, (void *) &query, &strategy, GIST_LEAF(entry), &tinfo, fcinfo->flinfo)
        );
}


Datum
gbt_date_distance(PG_FUNCTION_ARGS)
{
    GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
    DateADT        query = PG_GETARG_DATEADT(1);

    /* Oid        subtype = PG_GETARG_OID(3); */
    dateKEY    *kkk = (dateKEY *) DatumGetPointer(entry->key);
    GBT_NUMKEY_R key;

    key.lower = (GBT_NUMKEY *) &kkk->lower;
    key.upper = (GBT_NUMKEY *) &kkk->upper;

    PG_RETURN_FLOAT8(
                     gbt_num_distance(&key, (void *) &query, GIST_LEAF(entry), &tinfo, fcinfo->flinfo)
        );
}


Datum
gbt_date_union(PG_FUNCTION_ARGS)
{
    GistEntryVector *entryvec = (GistEntryVector *) PG_GETARG_POINTER(0);
    void       *out = palloc(sizeof(dateKEY));

    *(int *) PG_GETARG_POINTER(1) = sizeof(dateKEY);
    PG_RETURN_POINTER(gbt_num_union((void *) out, entryvec, &tinfo, fcinfo->flinfo));
}


Datum
gbt_date_penalty(PG_FUNCTION_ARGS)
{
    dateKEY    *origentry = (dateKEY *) DatumGetPointer(((GISTENTRY *) PG_GETARG_POINTER(0))->key);
    dateKEY    *newentry = (dateKEY *) DatumGetPointer(((GISTENTRY *) PG_GETARG_POINTER(1))->key);
    float       *result = (float *) PG_GETARG_POINTER(2);
    int32        diff,
                res;

    diff = DatumGetInt32(DirectFunctionCall2(
                                             date_mi,
                                             DateADTGetDatum(newentry->upper),
                                             DateADTGetDatum(origentry->upper)));

    res = Max(diff, 0);

    diff = DatumGetInt32(DirectFunctionCall2(
                                             date_mi,
                                             DateADTGetDatum(origentry->lower),
                                             DateADTGetDatum(newentry->lower)));

    res += Max(diff, 0);

    *result = 0.0;

    if (res > 0)
    {
        diff = DatumGetInt32(DirectFunctionCall2(
                                                 date_mi,
                                                 DateADTGetDatum(origentry->upper),
                                                 DateADTGetDatum(origentry->lower)));
        *result += FLT_MIN;
        *result += (float) (res / ((double) (res + diff)));
        *result *= (FLT_MAX / (((GISTENTRY *) PG_GETARG_POINTER(0))->rel->rd_att->natts + 1));
    }

    PG_RETURN_POINTER(result);
}


Datum
gbt_date_picksplit(PG_FUNCTION_ARGS)
{
    PG_RETURN_POINTER(gbt_num_picksplit(
                                        (GistEntryVector *) PG_GETARG_POINTER(0),
                                        (GIST_SPLITVEC *) PG_GETARG_POINTER(1),
                                        &tinfo, fcinfo->flinfo
                                        ));
}

Datum
gbt_date_same(PG_FUNCTION_ARGS)
{
    dateKEY    *b1 = (dateKEY *) PG_GETARG_POINTER(0);
    dateKEY    *b2 = (dateKEY *) PG_GETARG_POINTER(1);
    bool       *result = (bool *) PG_GETARG_POINTER(2);

    *result = gbt_num_same((void *) b1, (void *) b2, &tinfo, fcinfo->flinfo);
    PG_RETURN_POINTER(result);
}
